A randomised control trial of the effectiveness of personalised letters sent subsequent to school dental inspections in increasing registration in unregistered children

Recent studies have cast doubt on the effectiveness and efficiency of school based dental screening programmes in improving dental attendance or improving dental health. In 2002 the National Dental Inspection Programme was introduced in Scotland which categorises children by their dental health and informs parents of the findings via a personalised letter home and encourages dental registration. In addition, epidemiological data for local and national planning purposes is collected. This replaced an earlier school screening system in Lothian where a generic letter urging registration was sent to children who were identified as not being registered with a dentist. The objective of this study is to compare dental registrations rates among unregistered children in these two school inspection systems with a system where letters were sent home but no dental inspection was carried out.

The study was designed as a single blinded, cluster randomised, controlled trial involving 12,765 12–13-year-old children attending all 65 state Secondary schools in Lothian and Fife during the academic year 2003/4.

After stratifying for school size and range of social deprivation, schools were randomly allocated to one of four groups:

1. 'Traditional' inspection, letter to unregistered children only,

2. Letter sent home to unregistered children only, no inspection,

3. National Dental Inspection Programme, letter to all children,

4. Control group in which the children were neither inspected nor sent a letter.

Dental Registration status was compared at baseline and 3 months post inspection.

The registration levels in both the 'Traditional' screening and the NDIP inspection groups rose 3 months post inspection (14% and 15.8% respectively) but were not significantly different from one another or the control group which rose by 15.8% (p > 0.05). The group who were sent a letter home but were not inspected also has a rise in registration levels of 18.1% which was not significantly different from either of the groups who were inspected or the control group (p > 0.05). The only significant predictors of registration were previous registration (p < 0.05) and within those who previously registered, the length of time since last registration (P < 0.001).

Neither of the two dental inspection methods nor a letter home to unregistered children resulted in a significant rise in registration rates in 12–13-year-olds compared to a control group of children who received no intervention.